WO2015065040A1

WO2015065040A1 - Method and apparatus for transmitting modulation symbol using 256 qam in wireless access system

Info

Publication number: WO2015065040A1
Application number: PCT/KR2014/010247
Authority: WO
Inventors: 김봉회; 서동연; 안준기
Original assignee: 엘지전자 주식회사
Priority date: 2013-10-29
Filing date: 2014-10-29
Publication date: 2015-05-07
Also published as: US20150249564A1; US9531576B2

Abstract

The present invention relates to a wireless access system, and provides methods for designing 256 quadrature amplitude modulation (QAM) constellation points to support a 256 QAM modulation scheme and transmitting a modulation symbol using the 256 QAM constellation point and apparatuses supporting the same. In one embodiment of the present invention, a method of transmitting, by a transmitting side, a modulation symbol using a 256 QAM scheme may comprise the steps of: modulating eight bitstreams to one modulation symbol using a 256QAM modulation scheme; mapping the modulation symbol to one of 256 QAM constellation points; and transmitting the mapped modulation symbol.

Description

【Specification】

Title of the Invention

Method and apparatus for transmitting modulation symbols using 256QAM in a wireless access system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless access system and a method of designing a 256QAM constellation point to support a 256QAM (Quadrature Amplitude Modulation) modulation scheme, a method of transmitting a modulation symbol using the 256QAM constellation point, &Lt; / RTI >

BACKGROUND ART [0002]

[2] Wireless access systems are widely deployed to provide various types of communication services such as voice and data. In general, a wireless access system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access) systems. ᅳ

DETAILED DESCRIPTION OF THE INVENTION

[Technical Problem]

[3] Currently, LTE / LTE-A system adopts QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation) and 6 ⁴ QAM as the modulation method.

However, in order to increase the data transmission amount and to efficiently use radio resources, The use of 256QAM with degree is discussed. However, in order to support 256QAM, a new transport block size must be defined, and a new MCS signaling for supporting the 256QAM modulation scheme needs to be defined. Also, there is a need for a method of accurately mapping the symbols modulated by the 256QAM scheme onto constellation.

[4] An object of the present invention is to provide an efficient data transmission method.

Another object of the present invention is to provide a method for designing a constellation for supporting a 256QAM modulation scheme.

[6] Another object of the present invention is to provide a method and apparatus for decoding data using a 256QAM modulation scheme.

And a method for transmitting and receiving data.

[7] Another object of the present invention is to provide an apparatus supporting these methods.

The technical objectives to be achieved by the present invention are not limited to the above-mentioned matters, and other technical subjects which are not mentioned are to be understood from the embodiments of the present invention to be described below, &Lt; / RTI >

[Technical Solution]

The present invention relates to a wireless access system, and a method of designing a 256QAM constellation point to support a 256QAM modulation scheme, a method of transmitting a modulation symbol using the 256QAM constellation point, and devices supporting the modulation symbol are provided.

A method of transmitting a modulation symbol using a 256 QAM (Quadrature Amplitude Modulation) modulation scheme in a wireless access system in a wireless access system is a method of transmitting a modulation symbol through a 256QAM modulation scheme, &Lt; / RTI > Mapping the modulation symbols to one of the 256QAM constellation points and transmitting the mapped modulation symbols.

The method may further include transmitting an upper layer signal including an indicator indicating whether a transmitting terminal supports the 256QAM modulation scheme, selecting an MCS index indicating a 256QAM modulation scheme from the second table, and transmitting the selected MCS index to a receiving end As shown in FIG.

According to another aspect of the present invention, a transmitter for transmitting a modulation symbol using a 256QAM (Quadrature Amplitude Modulation) modulation scheme in a wireless access system may include a transmitter and a processor for supporting a 256QAM modulation scheme. At this time, the processor modulates the eight bit strings into one modulation symbol using the 256QAM modulation scheme; Map the modulation symbols to one of the 256 QAM constellation points; And to transmit the mapped modulation symbols using a transmitter.

In this case, the transmitting terminal controls the transmitter to transmit an upper layer signal including an indicator indicating whether the 256QAM modulation scheme is supported; And select the MCS index indicating the 256QAM modulation scheme from the second table and transmit it to the receiving end.

At this time, the MCS index can be displayed in a size of 5 bits.

[15] In aspects of the present invention, 256QAM constellation points can be configured as shown in the following figure.

[16] [Drawing]

In order to construct 256QAM constellation points, first 64QAM constellation points are arranged in the first quadrant, and 64QAM constellation points are constructed by imaginary axis symmetry, real axis symmetry and origin symmetry.

[18] The transmitting end can simultaneously manage the first table for supporting the legacy modulation scheme and the second table for supporting the 256QAM modulation scheme.

[19] In the downlink data transmission, the transmitting terminal may be a base station and the receiving terminal may be a terminal.

4 It is to be understood that both the foregoing general description and the following detailed description of the present invention are merely exemplary and are not to be construed as limiting the present invention. Various embodiments of the present invention will be apparent to those skilled in the art, And can be derived and understood based on the detailed description of the invention.

【Advantageous effect】

According to the embodiments of the present invention, the following effects can be obtained.

[22] First, data can be efficiently transmitted and received by transmitting / receiving data using a higher order modulation scheme.

[23] Second, by designing a new constellation to support 256QAM, data can be transmitted and received using a 256QAM modulation scheme.

The effects obtained in the embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be obtained from the description of the embodiments of the present invention described below, And can be clearly understood and understood by those of ordinary skill in the art. That is, undesirable effects of implementing the present invention can also be derived from those of ordinary skill in the art from the embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS [0027] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, provide illustrations of various embodiments of the invention. Further, the accompanying drawings are used to describe embodiments of the present invention in conjunction with the detailed description.

FIG. 1 is a view for explaining physical channels that can be used in embodiments of the present invention and a signal transmission method using the same. FIG. 2 shows a structure of a radio frame used in embodiments of the present invention.

3 is a diagram illustrating a resource grid for a downlink slot that can be used in embodiments of the present invention.

FIG. 4 shows a sphere S of an uplink sub-frame that can be used in embodiments of the present invention.

FIG. 5 illustrates a structure of a downlink subframe that can be used in embodiments of the present invention.

FIG. 6 is a diagram showing an example of carrier merging used in the composite carrier (CC) and the LTE_A system used in the embodiments of the present invention.

FIG. 7 illustrates a subframe structure of an LTE-A system according to cross-carrier scheduling used in embodiments of the present invention.

FIG. 8 is a diagram illustrating an example of a configuration of a serving cell according to cross carrier scheduling used in embodiments of the present invention.

FIG. 9 is a diagram illustrating an example of rate matching using a turbo coder that can be used in embodiments of the present invention.

FIG. 10 is a diagram illustrating one method of transmitting an MCS index for supporting 256QAM as an embodiment of the present invention.

FIG. 11 is a diagram illustrating an example of a constellation design method for supporting a 256 QAM modulation scheme.

FIG. 12 is a diagram illustrating another example of a constellation design method for supporting a 256 QAM modulation scheme. FIG. 13 is a diagram illustrating another method for designing constellation points for supporting a 256 QAM modulation scheme.

FIG. 14 is a diagram showing another method of designing constellation points for supporting a 256 QAM modulation scheme.

The apparatus shown in FIG. 15 is a means by which the methods described in FIGS. 1 to 14 can be implemented.

[Mode for Carrying Out the Invention]

Embodiments of the present invention relate to a wireless access system, in which a 256QAM constellation point is designed to support a 256QAM modulation scheme, and methods for transmitting a modulation symbol using the 256QAM constellation point and apparatuses supporting the 256QAM constellation point to provide.

The following embodiments combine the elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with counterpart configurations or features of other embodiments.

In the description of the drawings, there is no description of procedures or steps that may obscure the gist of the present invention, nor are descriptions of steps or steps that can be understood by those skilled in the art.

In the present specification, embodiments of the present invention have been described with reference to a data transmission / reception relationship between a base station and a mobile station. Here, the base station communicates directly with the mobile station It is meaningful as a terminal node of the network to be performed. The specific operation described herein as performed by the base station may be performed by an upper node of the base station, as the case may be.

That is, various operations performed for communication with a mobile station in a network including a plurality of network nodes including a base station can be performed by a base station or other network nodes other than the base station. At this time, the 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an Advanced Base Station (ABS) or an access point.

Also, in embodiments of the present invention, a terminal may be a user equipment (UE), a mobile station (MS), a subscriber station (SS), a mobile subscriber station (MSS) A subscriber station, a mobile terminal, or an advanced mobile station (AMS).

Also, the transmitting end refers to a fixed and / or mobile node providing data service or voice service, and the receiving end means a fixed and / or mobile node receiving data service or voice service. Therefore, in the uplink, the mobile station may be the transmitting end and the base station may be the receiving end. Similarly, in a downlink, a mobile station may be a receiving end and a base station may be a transmitting end.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the IEEE 802.xx system, the 3rd Generation Partnership Project (3GPP) system, the 3GPP LTE system and the 3GPP2 system, , Embodiments of the present invention may be supported by documents 3GPP TS 36.21 1, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321 and / or 3GPP TS 36.331. That is, in the embodiments of the present invention Explanatory steps or portions not described may be described with reference to the documents. In addition, all terms disclosed in this document may be described by the standard document.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention, and are not intended to be exhaustive or to limit the invention to the precise forms disclosed. .

For example, the term data block may be used interchangeably with the term transport block or transport block. The MCS / TBS index table used in the LTE / LTE-A system is defined as a first table or the legacy table, and the MCS / TBS index table for supporting the 256QAM proposed in the present invention is defined as a second table or a new table Can be defined.

[52] The following description is to be understood as exemplary embodiments of the present invention, which may be applied to various wireless communication systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA) ), And the like.

The CDMA may be implemented as a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented in a wireless technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be classified into IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA).

[54] UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) is a part of E-UMTS (Evolved UMTS) using E-UTRA _: adopts OFDMA in downlink and SC-FDMA in uplink. The LTE-A (Advanced) system is an improved 3GPP LTE system. In order to clarify the technical features of the present invention, the embodiments of the present invention are described mainly in the 3GPP LTE / LTE-A system, but can also be applied to the IEEE 802.16e / m system and the like.

[55] 1. 3GPP LTE / LTE_A system

In a wireless access system, a terminal receives information from a base station through a downlink (DL) and transmits information to a base station through an uplink (UL). The information transmitted and received between the base station and the terminal includes general data information and various control information, and there are various physical channels depending on the type / use of the information transmitted / received.

[57] 1.1 System General

FIG. 1 is a view for explaining a physical channel that can be used in embodiments of the present invention and a signal transmission method using the same.

In step S11, an initial cell search operation such as synchronizing with a base station is performed. The initial cell search operation is performed in step S11. To this end, the UE transmits a primary synchronization channel (P-SCH: Primary Synchronization Channel) and Secondary Synchronization Channel (S-SCH) to synchronize with the base station, and acquire information such as call ID.

After that, the UE can receive the physical broadcast channel (PBCH) signal from the base station and obtain the in-cell broadcast information. Meanwhile, the UE can receive the downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE receives a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to physical downlink control channel information in step S 12 So that more specific system information can be obtained.

[62] Thereafter, the terminal may perform a random access procedure such as steps S 13 to S 16 to complete the connection to the base station. To this end, the MS transmits a preamble (PRAM) through a physical random access channel (PRACH) (S13), and transmits a preamble message for the preamble through the physical downlink control channel and the corresponding physical downlink shared channel (S14). In the case of a contention-based random access, the UE transmits a physical random access channel signal (S15), a Physical Downlink Control Channel (PDCCH) signal and a Physical Contention Resolution Procedure can be performed.

The MS having performed the procedure described above transmits a physical downlink control channel signal and / or physical downlink shared channel signal (S17) and a physical uplink shared channel PUSCH (Physical Uplink Shared Channel) signal And / or transmission of a physical uplink control channel (PUCCH) signal (S18).

The control information transmitted from the UE to the BS is collectively referred to as Uplink Control Information (UCI). The UCI includes HARQ-ACK / NACK (Hybrid Automatic Repeat and Request Acknowledgment / Negative-ACK), SR (Scheduling Request), CQI (Channel Quality Indication), PMI (Precoding Matrix Indication) .

In the LTE system, the UCI is periodically transmitted through the PUCCH, but may be transmitted through the PUSCH when the control information and the traffic data are to be simultaneously transmitted. In addition, UCI can be transmitted non-periodically through the PUSCH according to the request / instruction of the network.

FIG. 2 illustrates a structure of a radio frame used in embodiments of the present invention.

2 (a) shows a type 1 frame structure (frame structure type 1). The Type 1 frame structure can be applied to both full duplex (FDD) and half duplex (FDD) systems.

A = have a length of ^{^{10 ms, iot = 15360 · τ}} 5 = 0 ' having a uniform length of ^{5 ms} of the 19 indexes from 0 grant; [68] one of a radio frame (radio frame) is = 307 200 .7 It consists of 20 slots. One subframe is defined as two consecutive slots, and the i-th subframe is composed of slots corresponding to 2i and 2i + l. That is, a radio frame is composed of 10 subframes. The time required to transmit one subframe is referred to as a transmission time interval (TTI). Here, Ts represents the sampling time, and is represented by Ts = l / (15 kHz x 2048) = 3.2552 x 10-8 (about 33 ns). Slot is time And includes a plurality of resource blocks in the frequency domain. The OFDM symbol or the SC-FDMA symbol includes a plurality of resource blocks in the frequency domain.

[69] One slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain. Since 3GPP LTE uses OFDMA in the downlink, an OFDM symbol is used to represent one symbol period. The OFDM symbol may be one SC-FDMA symbol or a symbol interval. A resource block is a resource allocation unit and includes a plurality of consecutive subcarriers in one slot.

In the full-duplex FDD system, 10 subframes can be used simultaneously for downlink transmission and uplink transmission for each 10 ms interval. At this time, the uplink and downlink transmissions are separated in the frequency domain. On the other hand, in the case of a half-duplex FDD system, the UE can not transmit and receive simultaneously.

The structure of the radio frame described above is only one example, and the number of subframes included in a radio frame, the number of slots included in a subframe, and the number of OFDM symbols included in a slot can be variously changed have.

FIG. 2 (b) shows a type 2 frame structure (frame structure type 2). The Type 2 frame structure is applied to the TDD system. One radio frame (radio frame) is ^{^{_{f = 3 0 72 00.r s =}}} 10 m has a length _{^{S, l 536 0 ().}} R s = (half-frame) 2 having a one half frame length ⁵ _ms . Each half frame consists of 5 subframes with a length of ^{3 (} > ^72, 7 = 1 ms). The i-th subframe consists of 2i and 2i + l, corresponding to each r _slot = l ⁵³⁶ 0'r _s = It consists of _two slots having a length of ⁵ ms. here, Ts represents the sampling period is represented by Ts = l / (15kHzx2048) = 3.2552x l0-8 ( about 33ns). A Type 2 frame includes a special subframe consisting of three fields: a Downlink Pilot Time Slot (DwPTS), and a Guard Period (GP) _: Uplink Pilot Time Slot (UPPTS). Here, DwPTS is used for initial cell search, synchronization, or channel estimation in the UE. UpPTS is used to match the channel estimation at the base station and the uplink transmission synchronization of the terminal. The guard interval is a period for eliminating the interference occurring in the uplink due to the multi-path delay of the downlink signal between the uplink and the downlink.

Table 1 below shows the composition of the special frame (DwPTS / GP UpPTS length).

[75] Table 1

Referring to FIG. 3, one downlink slot includes a plurality of OFDM symbols in a time domain. Herein, one downlink slot includes 7 OFDM symbols, and one resource block includes 12 subcarriers in the frequency domain. However, the present invention is not limited thereto. [78] Each element on the resource grid is a resource element, and one resource block includes 12 X 7 resource elements. The number of resource blocks NDL included in the downlink slot is dependent on the downlink transmission bandwidth. The structure of the uplink slot may be the same as the structure of the downlink slot.

FIG. 4 illustrates a structure of an uplink subframe that can be used in embodiments of the present invention.

Referring to FIG. 4, an uplink subframe can be divided into a control region and a data region in a frequency domain. A PUCCH for carrying UL control information is allocated to the control region. The data area is assigned a PUSCH carrying user data. To maintain a single carrier characteristic, one UE does not transmit PUCCH and PUSCH at the same time. An RB pair is allocated to a PUCCH for one UE in a subframe. RBs belonging to the RB pair occupy different subcarriers in each of the two slots. It is assumed that the RB pair assigned to the PUCCH is frequency hopped at the slot boundary.

Referring to FIG. 5, in a first slot in a subframe, a maximum of 3 OFDM symbols are allocated to a control region in which control channels are allocated, and the remaining OFDM symbols are allocated to a data region data region). Examples of the downlink control channel used in 3GPP LTE include a Physical Control Format Indicator Channel (PCFICH), a PDCCH, and a Physical Hybrid-ARQ Indicator Channel (PHICH). The PCFICH is carried in the first OFDM symbol of the subframe and carries information about the number of OFDM symbols (ie, the size of the control region) used for transmission of control channels in the subframe. The PHICH is an uplink channel for the uplink and carries an ACK (Acknowledgment) / NACK (Negative-Acknowledgment) signal for HARQ (Hybrid Automatic Repeat Request). The control information transmitted through the PDCCH is referred to as downlink control information (DCI). The downlink control information includes uplink resource allocation information, downlink resource allocation information, or an uplink transmission (Tx) power control command for an arbitrary terminal group. [84] 1.2 Physical Downlink Control Channel (PDCCH)

[85] 1.2.1 PDCCH General

The PDCCH includes resource allocation and transmission format (DL-Grant) of DL-SCH (Downlink Shared Channel), resource allocation information of UL-SCH (uplink grant) (UL-Grant), paging information in a paging channel (PCH), system information in a DL-SCH, and a random access response transmitted on a PDSCH A resource allocation for a message, a set of transmission power control commands for individual terminals in an arbitrary terminal group, information on whether to activate a VoIP (Voice over IP), and the like.

A plurality of PDCCHs may be transmitted in a control region, and a UE may monitor a plurality of PDCCHs. The PDCCH consists of one or several consecutive aggregation of control channel elements (CCEs). A PDCCH composed of a set of one or several consecutive CCEs can be transmitted through the control domain after subblock interleaving. The CCE determines the coding rate according to the state of the radio channel PDCCH. &Lt; / RTI > The CCE corresponds to a plurality of resource element groups (REGs). The format of the PDCCH and the number of bits of the possible PDCCH are determined according to the relationship between the number of CCEs and the coding rate provided by the CCEs.

[88] 1.2.2 PDCCH Structure

A plurality of multiplexed PDCCHs for a plurality of terminals may be transmitted in a control region. The PDCCH consists of one or two or more consecutive CCE aggregations. A CCE is a unit corresponding to nine sets of REGs composed of four resource elements. Each REG is mapped to four quadrature phase shift keying (QPSK) symbols. Resource elements occupied by a reference signal (RS) are not included in the REG. That is, the total number of REGs in an OFDM symbol may vary depending on whether a cell specific reference signal is present or not. The concept of a REG that maps four resource elements to one group can be applied to other downlink control channels (e.g., PCFICH or PHICH). Assuming that the REG that are not assigned to the PCFICH or PHICH number of CCE available in the system is ^, and CCE = [^ 1 ^0/9 ", each CCE is from 0 ^ CCE - has an index to the I.

In order to simplify the decoding process of the UE, the PDCCH format including n CCEs can be started from a CCE having the same index as a multiple of n. That is, if the CCE index is i, it can be started from CCE satisfying imod " = 0.

The base station can use {1, 2, 4, 8} CCEs to construct one PDCCH signal, and {1, 2, 4, 8} at this time is a CCE aggregation level I call it. The number of CCEs used for transmission of a specific PDCCH is determined by the BS according to the channel state. For example, a PDCCH for a UE having a good downlink channel state (when it is close to a base station) can be divided into one CCE only. On the other hand, in the case of a terminal having a bad channel condition (in the cell boundary), eight CCEs may be required for sufficient robustness. In addition, the power level of the PDCCH can be adjusted to match the channel state.

Table 2 below shows the PDCCH format. Four PDCCH formats are supported as shown in Table 2 according to the CCE aggregation level. [93] [Table 2]

PDCCH format Number of CCEs (n) Number of REGs Number of PDCCH bits

0 I 9 72

1 2 18 144

2 4 36 288

3 8 72 576

The reason why the CCE aggregation level differs from terminal to terminal is that the format of the control information carried on the PDCCH or the modulation and coding scheme (MCS) level is different. The MCS level refers to a code rate and a modulation order used for data coding. The sole MCS level is used for link adaptation. In general, three to four MCS levels can be considered in a control channel for transmitting control information.

The format of the control information will be described. Control information transmitted through the PDCCH is referred to as downlink control information (DCI). The configuration of the information carried in the PDCCH payload may vary depending on the DCI format. The PDCCH payload means an information bit. Table 3 below shows the DCI according to the DCI format. [96] [Table 3]

Referring to Table 3, in the DCI format, a format 0 for PUSCH scheduling, a format 1 for scheduling one PDSCH codeword, a format 1A for compact scheduling of one PDSCH codeword, a DL- SCH for very simple scheduling, format 2 for PDSCH scheduling in a closed-loop spatial multiplexing mode, format 2A for PDSCH scheduling in an open loop spatial multiplexing mode, There are formats 3 and 3A for transmission of TPC (Transmission Power Control) commands for the channel. Also, DCI format 4 for PUSCH scheduling is added in multi-antenna port transmission mode. The DCI format 1A can be used for PDSCH scheduling regardless of which transmission mode is set in the UE.

The PDCCH payload length may vary depending on the DCI format. In addition, the type of the PDCCH payload and the length thereof may vary depending on whether it is a compact scheduling or a transmission mode set in the UE.

The transmission mode may be configured such that the UE receives downlink data on the PDSCH. For example, downlink data on the PDSCH includes scheduled data for the UE, paging, random access response, or broadcast information on the BCCH. The downlink data through the PDSCH is transmitted through the PDCCH It is related to the DCI format being signaled. The transmission mode may be semi-statically set to the terminal via higher layer signaling (e.g., Radio Resource Control (RRC) signaling). The transmission mode can be classified into a single antenna transmission or a multi-antenna transmission.

[100] The terminal sets a transmission mode in a semi-static manner through upper layer signaling. For example, the multi-antenna transmission may include transmission diversity, open-loop or closed-loop spatial multiplexing, MU-MIMO (Multi-User-Multiplexed Input Multiple Output ) Or beam forming (Beamforming). Transmit diversity is a technique for increasing transmission reliability by transmitting the same data in multiple transmit antennas. Spatial multiplexing is a technique capable of transmitting high-speed data without increasing the bandwidth of the system by simultaneously transmitting different data from multiple transmit antennas. Beamforming is a technique for increasing the SINR (Signal to Interference plus Noise Ratio) of a signal by applying a weight according to channel conditions in multiple antennas.

[101] The DCI format depends on the transmission mode set in the UE. The UE has a reference DCI format for monitoring according to the transmission mode set for the UE. The transmission mode set in the UE can have 10 transmission modes as follows.

, Transmission mode 1: single antenna transmission

, Transmission mode 2: transmit diversity

Transmission mode 3: Open-loop codebook-based precoding when the layer is larger than 1, transmit diversity when the rank is 1,

Transmission mode 4: Closed-loop codebook-based precoding

Transmission mode 5: Transmission mode Four versions of multi-user MIMO , Transmission mode 6: closed loop codebook based precoding in a special case limited to single layer transmission "

, Transmission mode 7: precoding (release 8) based not on a codebook supporting only single layer transmission,

Transmission mode 8: Precoding (release 9) based not on codebooks supporting up to two layers

* Transmission mode 9: Precoding (release 10) based not on codebooks supporting up to 8 layers.

* Transmission mode 10: precoding not based on a codebook supporting up to 8 layers, use of COMP (release 11)

[102] 1.2.3 PDCCH transmission

The base station determines the PDCCH format according to the DCI to be transmitted to the UE, and attaches a CRC (Cyclic Redundancy Check) to the control information. The CRC is masked with a unique identifier (e.g., Radio Network Temporary Identifier (RNTI)) according to the owner or use of the PDCCH. A unique identifier (e.g., C-RNTI (Cell-RNTI)) of the UE may be masked in the CRC if it is a PDCCH for a particular UE. Or a PDCCH for a paging message, a paging indication identifier (e.g., P-RNTI (P-RNTI)) may be masked to the CRC. System information identifiers (e.g. SI-R TI (system information RNTI)) can be masked to the CRC if the PDCCH is for a system information, more specifically a system information block (SIB). A random access-RNTI (RA-RNTI) may be masked in the CRC to indicate a random random access response to the transmission of the UE's random access preamble. The base station then performs coded coding on the control information to which the CRC is added to generate coded data. At this time, channel coding can be performed at a code rate according to the MCS level. The base station performs rate matching according to the CCE aggregation level allocated to the PDCCH format, and modulates the coded data to generate modulation symbols. At this time, a modulation sequence according to the MCS level can be used. The modulation symbols constituting one PDCCH may be one of CCE aggregation levels 1, 2, 4, and 8. The base station then maps the modulation symbols to a physical resource element (CCE to RE mapping).

1.2.4 Blind Decoding (BS)

A plurality of PDCCHs can be transmitted in one subframe. That is, the control region of one subframe is composed of a plurality of CCEs having indexes 0 to ^N CCEJ ^C - ^. Here, ^NcCE ^'k is the number of total CCE in a control region of the k-th subframe. The UE monitors a plurality of PDCCHs in every subframe. Here, monitoring refers to the UE attempting to decode each of the PDCCHs according to the PDCCH format being monitored.

In the control region allocated in the subframe, the BS does not provide information on where the corresponding PDCCH is located to the UE. Since the UE can not know from which position its CCE aggregation level or DCI format is transmitted in order to receive the control channel transmitted from the Node B, the UE monitors the set of PDCCH candidates in the subframe, Lt; / RTI > This is referred to as blind decoding (BD). In the blind decoding, (De-Masking) an identifier (UE ID), examining a CRC error, and checking whether the corresponding PDCCH is its own control channel.

In the active mode, the UE monitors the PDCCH of each subframe in order to receive data transmitted to the UE. In the DRX mode, the UE wakes up in a monitoring interval of every DRX period and monitors the PDCCH in a subframe corresponding to the monitoring interval. The subframe in which the PDCCH is monitored is called a non-DRX subframe.

In order to receive the PDCCH transmitted to the UE, the UE must perform blind decoding on all CCEs present in the control region of the non-DRX subframe. Since the UE does not know which PDCCH format is to be transmitted, the UE must decode all of the PDCCHs at a possible CCE aggregation level until the blind decoding of the PDCCH succeeds in every non-DRX subframe. Since the UE does not know how many CCEs the PDCCH for itself uses, it should try to detect all possible CCE aggregation levels until the blind decoding of the PDCCH succeeds.

[110] In the LTE system, a search space (SS) concept is defined for blind decoding of a terminal. The search space refers to a PDCCH candidate set for monitoring by the UE, and may have a different size according to each PDCCH format. The search space may be composed of a common search space (CSS) and a UE-specific / dedicated search space (USS).

In the case of [111] common search space, all terminals can know the size of the common search space, but terminal specific search spaces can be set individually for each terminal. Accordingly, the UE can use the UE-specific search space and the UE- It is necessary to monitor all of the public search spaces,

And performs blind decoding (BD) of 44 times. But does not include blind decoding performed according to different CRC values (e.g., C-RNTI, P-RNTI, SI-R TI, RA-RNTI).

Due to the restriction of the search space, the BS may not be able to secure the CCE resources for transmitting the PDCCH to all the UEs to which the PDCCH is to be transmitted in a given subframe. This is because the CCE location is allocated and the remaining resources may not be included in the search space of the specific terminal. In order to minimize such a barrier that may continue in the next sub-frame, the UE can be applied to the start point of the UE-specific search space during UE-specific hopping.

Table 4 shows the sizes of the public search space and the UE-specific search space.

[114] Table 4

Number of CCEs Number of candidates

PDCCH format (») in common search space in dedicated search space

0 1 - 6

Γ 2 - 6

2 4 4 2

3 8 2 2

In order to reduce the load of the UE according to the number of attempts to perform the blind decoding, the UE does not simultaneously search according to all defined DCI formats. Specifically, the terminal always searches for DCI format 0 and 1A in the UE-specific search space. At this time, DCI format 0 and 1A have the same size, but the UE can distinguish the DCI format using a flag (for format 0 / format 1A differentiation) used for distinguishing DCI format 0 and 1A included in the PDCCH. In addition, when the terminal receives DCI format 0 A DCI format other than DCI format 1A may be required, for example DCI format 1, IB, 2.

In the public search space, the terminal can search the DCI formats 1A and 1C. Also, the terminal can be set to search for DCI format 3 or 3A, and DCI formats 3 and 3A have the same size as DCI formats 0 and 1A, but the terminal uses the scrambled CRC by an identifier other than the terminal specific identifier DCI format can be distinguished.

The search space means a PDCCH candidate set according to the set level {1, 2, 4, 8}. The CCE according to the PDCCH candidate set w of the search space can be determined by the following Equation (1).

[118] < EMI ID = 1.0 >

Here, ^ ^(£) denotes the number of PDCCH candidates according to the CCE aggregation level L for monitoring in the search space and is = 0 '' M ⁽ⁱ ) - l. I denotes an individual CCE in each _PDCCH candidate 7, as an index to ^'= 0, "", ^ - 1 a = L "is s / ² J, represents a slot index within a radio frame.

As described above, the UE monitors both the UE-specific search space and the common search space in order to decode the PDCCH. Here, the common search space CSS supports PDCCHs having aggregate levels of {4, 8}, and the UE-specific search space USS supports PDCCHs having aggregate levels of {1, 2, 4, 8} . Table 5 shows the PDCCH candidates monitored by the UE.

[121] [Table 5] Search space Number of PDCCH

candidates

Type Aggregation level L Size [in CCEs] M ⁽

1 6 6

UE-2 12 6

specific 4 8 2

8 16 2

4 16 4

Common

8 16 2

Referring to Equation (1), in the case of the common search space, two sets of levels, L = 4 and

And is set to 0 for L = 8. On the other hand, for the aggregation level L, the case of the UE-specific search space is defined as shown in Equation (2).

[123] " (2) "

Y _k = (A - Y _k _) mod D

Here, ^y -i ⁼ "RNTI ≠ ⁰ , ⁿ n indicates the RNTI value, and = ³⁹⁸²⁷ and Z = 65537.

2. Carrier Aggregation (CA) Environment

[126] 2.1 CA General

A 3GPP LTE (Relay-8 or Rel-9) system (hereinafter referred to as LTE system) is a multi-carrier modulation (MCM: Multi-Carrier Modulation). However, in the 3GPP LTE-Advanced system (hereinafter referred to as LTE-A system), a method such as Carrier Aggregation (CA: Carrier Aggregation) in which one or more component carriers are combined to support a system bandwidth of a wide band have. Carrier coupling may be replaced by words such as carrier aggregation, carrier matching, multi-component carrier environments (Multi-CC), or multi-carrier environments. In the present invention, a multi-carrier refers to a combination of carriers (or carrier aggregation), in which the combination of carriers means both a combination of contiguous carriers as well as a combination of non-contiguous carriers . In addition, the number of component carriers aggregated between the downlink and the uplink may be set differently. The case where the number of downlink component carriers (DL CC) is equal to the number of uplink component carriers (UL CC) is referred to as a symmetric combination, It is called asymmetric bonding. Such carrier coupling can be widely used with terms such as carrier aggregation, bandwidth aggregation, spectrum aggregation, and the like.

A carrier combination in which two or more component carriers are combined is aimed at supporting up to 100 MHz bandwidth in the LTE-A system. When combining one or more carriers with a bandwidth smaller than the target bandwidth, the bandwidth of the combining carrier can be limited to the bandwidth used in the existing system to maintain backward compatibility with the existing IMT system.

For example, the existing 3GPP LTE system supports {1.4, 3, 5, 10, 15, 20} MHz bandwidth and 3GPP LTE-advanced system (ie LTE-A) It is possible to support bandwidths greater than 20 MHz using only the above-mentioned bandwidths. Also, the carrier combining system used in the present invention may support carrier combining by defining a new bandwidth regardless of the bandwidth used in the existing system. ^'

In addition, the carrier combination may be divided into an intra-band CA and an inter-band CA. Intra-band carrier binding refers to multiple DL CC And / or UL CCs are located adjacent or close in frequency. In other words, it may mean that the carrier frequencies of DL CC and / or UL CC are located in the same band. On the other hand, an environment far from the frequency domain may be referred to as an inter-band CA. In other words, it may mean that the carrier frequencies of multiple DL CCs and / or UL CCs are located in different bands. In this case, the UE may use a plurality of radio frequency (RF) stages to perform communication in a carrier-combining environment.

[132] The LTE-A system uses the concept of a cell to manage radio resources. The above-described carrier binding environment may be referred to as a multiple cell environment. The SAL is defined as a combination of a downlink resource (DL CC) and a pair of uplink resources (UL CC), but the uplink resource is not essential. Therefore, the cell can be composed of downlink resources alone or downlink resources and uplink resources.

For example, if a particular UE has only one configured serving cell, it can have one DL CC and one UL CC. However, if a UE has two or more established serving cells And the number of UL CCs may be equal to or less than the number of DL CCs. Alternatively, DL CC and UL CC may be configured. That is, a carrier combining environment in which UL CC is larger than the number of DL CCs can be supported when a specific UE has a plurality of set serving sorts.

Further, the carrier combination (CA) can be understood as a combination of two or more seals each having a different carrier frequency (center frequency of the cell). Here, the term 'cell' should be distinguished from a 'cell' as a geographical area covered by a commonly used base station. Below, The intra-band carrier combination described above is referred to as intra-band multi-cell, and the inter-band carrier combination is referred to as inter-band multi-cell.

In the LTE-A system, a SAL used includes a primary cell (PCell) and a secondary cell (SCell). Psal and Ssal can be used as Serving Cells. For a UE that is in the RRC_CONNECTED state but no carrier binding is set or does not support carrier binding, there is only one serving cell consisting of P cells only. On the other hand, in the case of the UE in the RRC_CONNECTED state and the UE having the carrier combination established, there may be one or more serving cells, and the entire serving cell includes the P cell and one or more S cells.

The serving cell (P-cell and S-cell) can be set through the RRC parameter. PhysCellld is the physical layer identifier of the cell and has an integer value from 0 to 503. SCelllndex is a short identifier used to identify an S cell and has an integer value from 1 to 7. ServCelllndex is a short identifier used to identify the serving cell (P sal or S cell) and has an integer value from 0 to 7. A value of 0 is applied to the P-cell, and SCelllndex is given beforehand to apply to S-SAL. That is, a cell having the smallest cell ID (or cell index) in ServCelllndex becomes a P cell.

P cell refers to a cell operating on the primary frequency (or primary CC). The UE may be used to perform an initial connection establishment process or a connection reestablishment process, and may refer to a cell indicated in the handover process. In addition, the P cell means a cell that is the center of control related communication among the serving cells set in the carrier combining environment. That is, the UE can allocate and transmit PUCCH only in its own P-cell, acquire system information or change the monitoring procedure P cells can be used. The Evolved Universal Terrestrial Radio Access (E-UTRAN) changes only the P cell for the handover procedure by using the RRC connection re-establishment message of the upper layer including the mobility control information (mobilityControlInfo) It is possible.

An S-cell may mean a cell that operates on a secondary frequency (or secondary CC). Only one p-cell is allocated to a specific terminal, and one or more S-cells can be allocated. The S-cell is configurable after the RRC connection is established and can be used to provide additional radio resources. Among the serving cells set in the carrier combining environment, there are no PUCCHs in the remaining cells except for the P cell, i.e., the S cell.

When the E-UTRAN adds an S-cell to a UE supporting a carrier-combining environment, the E-UTRAN can provide all the system information related to the operation of the related cell in the RRC-CONNECTED state through a dedicated signal . A change in the system information can be controlled by releasing and adding the associated S-cell, where the RRConnectionReconfigu- tion message of the upper layer can be used. The E-UTRAN may perform dedicated signaling with different parameters for each UE rather than broadcast within the associated S-cell.

After the initial security activation process is started, the E-UTRAN may configure a network including one or more S cells in addition to the P cell initially configured in the connection establishment process. In a carrier-combining environment, P-cells and S-cells may operate as respective component carriers. In the following embodiments, the primary component carrier (PCC) may be used in the same sense as the P cell, and the secondary component carrier (SCC) may be used in the same meaning as the S cell. FIG. 6 is a diagram showing an example of a carrier combination used in a component carrier (CC) and an LTE_A system used in embodiments of the present invention.

FIG. 6 (a) shows a single carrier structure used in an LTE system. The component carriers have DL CC and UL CC. One component carrier may have a frequency range of 20 MHz.

FIG. 6 (b) shows a carrier bonding structure used in the LTE-A system. And FIG. 6 (b) shows a case where three component carriers having a frequency magnitude of 20 MHz are combined. There are three DL CCs and three UL CCs, but the number of DL CCs and UL CCs is not limited. In the case of carrier combination, the UE can simultaneously monitor three CCs, receive downlink signals / data, and transmit uplink signals / data.

If N DL CCs are managed in a specific cell, the network can allocate M (M ≦ N) DL CCs to the UE. At this time, the terminal can monitor only M restricted DL CCs and receive DL signals. In addition, the network may assign a priority DL CC to a terminal by giving priority to L (L? M? N) DL CCs, and in this case, the UE must monitor L DL CCs. This scheme can be equally applied to uplink transmission.

The linkage between the carrier frequency (or E> L CC) of the downlink resource and the carrier frequency (or UL CC) of the uplink resource may be indicated by an upper layer message or system information such as an RRC message . For example, a combination of a DL resource and a UL resource may be configured by a linkage defined by SIB2 (System Information Block Type 2). Specifically, the linkage is transmitted to the DL to which the PDCCH carrying the UL grant is transmitted (Or UL CC) in which data for HARQ is transmitted and a UL CC (or DL CC) in which an HARQ ACK / NACK signal is transmitted may be a mapping relationship between the CC and the UL CC using the UL grant. It can also mean a mapping relationship. [146] 2.2 Cross Carrier Scheduling [

There are two methods in a carrier-combining system: a self-scheduling method and a cross-carrier scheduling method in terms of scheduling for a carrier (or a carrier wave) or a serving cell. Cross-carrier scheduling may be referred to as Cross Component Carrier Scheduling or Cross Cell Scheduling.

In the self-scheduling, the PDCCH and the PDSCH are transmitted in the same DL CC, or the PUSCH transmitted according to the PDCCH (UL Grant) transmitted in the DL CC is transmitted to the UL CC Lt; / RTI >

In the cross carrier scheduling, the PDCCH (DL Grant) and the PDSCH are transmitted in different DL CCs, or the PUSCH transmitted according to the PDCCH (UL Grant) transmitted in the DL CC is linked to the DL CC receiving the UL grant And is transmitted through a UL CC other than the UL CC.

The cross-carrier scheduling can be UE-specific activated or deactivated and can be semi-staticly informed for each UE through upper layer signaling (eg, RRC signaling) .

When cross-carrier scheduling is activated, a carrier indicator field (CIF: Carrier Indicator Field) indicating which DL / UL CC the PDSCH / PUSCH indicated by the corresponding PDCCH is transmitted to via the PDCCH is required. For example, the PDCCH may be a PDSCH resource or The PUSCH resource may be assigned to one of a number of component carriers using CIF. That is, the CIF is set when the PDCCH on the DL CC allocates PDSCH or PUSCH resources to one of the DL / UL CCs that are multi-aggregated. In this case, the DCI format of LTE Release-8 can be extended according to CIF. At this time, the set CIF may be fixed to the 3-bit field or the position of the set CIF may be fixed regardless of the DCI format size. In addition, the PDCCH structure (same coding and resource mapping based on the same CCE) of LTE Release-8 can be reused.

On the other hand, when the PDCCH on the DL CC allocates PDSCH resources on the same DL CC or allocates PUSCH resources on a single linked UL CC, the CIF is not set. In this case, the same PDCCH structure (same coding and same CCE-based resource mapping) and DCI format as LTE Release-8 can be used.

When cross carrier scheduling is possible, the UE needs to monitor the PDCCHs for a plurality of DCIs in the control region of the monitoring CC according to the transmission mode and / or bandwidth for each CC. Therefore, the configuration of the search space and PDCCH monitoring that can support it are needed.

In a carrier-combining system, a terminal DL CC aggregation represents a set of DL CCs scheduled to receive a PDSCH by a UE, and a UL CC aggregation represents a set of UL CCs scheduled for a UE to transmit a PUSCH. Also, the PDCCH monitoring set represents a set of at least one DL CC that performs PDCCH monitoring. The PDCCH monitoring set may be the same as the terminal DL CC set or may be a subset of the terminal DL CC set. The PDCCH monitoring set may include at least one of the DL CCs in the terminal DL CC set. Alternatively, the PDCCH monitoring set may include a DL CC It can be defined separately regardless of the set. The DL CC included in the PDCCH monitoring set can be set to always enable self-scheduling for the linked UL CC. The terminal DL CC set, the terminal UL CC set, and the PDCCH monitoring set may be UE-specific, UE group-specific, or cell-specific.

When the cross-carrier scheduling is deactivated, it means that the PDCCH monitoring set is always the same as the terminal DL CC set. In this case, an instruction such as separate signaling for the PDCCH monitoring set is not required. However, if cross-carrier scheduling is enabled, it is desirable that the PDCCH monitoring set is defined within the terminal DL CC set. That is, in order to schedule the PDSCH or the PUSCH to the UE, the BS transmits the PDCCH only through the PDCCH monitoring set.

Referring to FIG. 7, three downlink component carriers (DL CCs) are combined in the DL subframe for the LTE-A UE, and DL CC 'A' is set to the PDCCH monitoring DL CC. If CIF is not used, each DL CC can send a PDCCH that schedules its PDSCH without CIF. On the other hand, when the CIF is used through upper layer signaling, only one DL CC 'A' can transmit a PDCCH that schedules its PDSCH or another CC's PDSCH using the CIF. At this time, DL CC 'and' C not set to PDCCH monitoring DL CC do not transmit PDCCH. FIG. 8 is a diagram illustrating an example of a configuration of a serving cell according to cross carrier scheduling used in embodiments of the present invention.

In a wireless access system supporting Carrier Binding (CA), a base station and / or terminals may be composed of one or more serving cells. In FIG. 8, the base station can support a total of four serving sams including A sal, B cell, C cell and D cell, terminal A is composed of A cell, B sal and C cell, terminal B is B cell, D cells, and terminal C is composed of B cells. At this time, at least one of the cells configured in each terminal may be set as a P-cell. At this time, the P cell is always active, and the S cell can be activated or deactivated by the base station and / or the terminal.

The cell configured in FIG. 8 is a cell that can be added to a CA based on a measurement report message from a terminal among the cells of the base station, and can be set for each terminal. The configured cell reserves resources for ACK / NACK message transmission for PDSCH signal transmission in advance. The activated cell is set to transmit actual PDSCH signal and / or PUSCH signal among the configured cells, and performs CSI reporting and SRS (Sounding Reference Signal) transmission. The De-Activated cell is a cell configured to not transmit / receive a PDSCH / PUSCH signal by a command or a timer operation of the base station, and the CSI report and SRS transmission are also interrupted. [161] 3. Channel encoding

In a wireless access system, in order to correct an error experienced in a wireless channel by a receiving end, a transmitting end performs coding using forward error correction code for information, signal, and / or message to be transmitted, Lt; / RTI > The receiver demodulates the received signal and then decodes the error correcting code to recover the received signal. In this decryption process, the receiving end can correct the error on the received signal caused by the wireless channel. Various types of error correction codes can be used, but in the present invention, a turbo code will be described as an example.

A turbo coder consists of a recursive systematic convolution code and an interleaver. In actual implementation of turbo codes, there is an interleaver to facilitate parallel decoding, one of which is Quadratic Polynomial Permutation (QPP). Such a QPP interleaver exhibits good performance for a specific size of a transport block (i.e., a data block), and the performance of the turbo code is better as the size of a transport block increases. Accordingly, in the wireless access system, in order to facilitate the implementation of the turbo code, a transmission block having a predetermined size or larger is divided into a plurality of small transport blocks for encoding. At this time, the divided small transport block is called a code block.

Although code blocks generally have the same size, one of the code blocks may have different sizes because of the size limitation of the QPP interleaver. The transmitting end performs an error correction coding process in units of code blocks of the interleaver. For example, referring to FIG. 9, one code block is input to the turbo coder 910. The turbo coder 910 performs 1/3 coding on the input code block to output a systematic block and parity blocks 1 and 2. After that, the transmitting end performs interleaving for each block using the sub-block interleaver 930 in order to reduce the influence of the burst errors that may occur in transmission on the wireless channel. Then, the transmitting end maps the interleaved code block to the actual radio resource and transmits the same.

Since the amount of radio resources used in transmission is constant, in order to match the amount of radio resources used in transmission, the transmitting terminal performs rate matching on the encoded code blocks. In general, the rate matching is performed by puncturing or repetition of the data.

The rate matching can be performed in code block units such as 3GPP WCDMA. Alternatively, the systematic block and the parity block of the encoded code block may be separated and interleaved separately. As described above, FIG. 9 shows that rate matching is performed by separating systematic blocks and parity bits.

A CRC (Cyclic Redundancy Code) for error detection is attached to a transmission block transmitted from an upper layer of a transmitter, and a CRC is attached to each code block to which a transmission block is divided. Various transport block sizes should be defined according to the service type of the upper layer. The transmitting end performs quantization to transmit the transmission blocking to the receiving end. To quantize the transport block, a dummy bit is added to match the transport block size of the physical layer with the source transport block transmitted from the upper layer. At this time, it is preferable to perform quantization so that the amount of dummy bits to be added is minimized. In embodiments of the present invention, the transport block size (TBS), the modulation and coding rate (MCS), and the number of allocated resources have a functional relationship with each other. That is, the remaining parameters are determined according to the values of the two parameters. Therefore, when the transmitting terminal and / or the receiving terminal signals the parameters, the transmitting terminal and / or the receiving terminal need only inform the other of the two parameters out of the three parameters.

Hereinafter, for the convenience of description of the present invention, it is assumed that modulation and coding schemes (MCS) and parameters related to the number of allocated resources are used to notify a receiving end of a transmission block size.

Factors affecting the number of allocated resources include a pilot or a reference signal (RS) for performing channel estimation according to the antenna configuration, and a resource used for transmitting control information. These factors can change at every moment of transmission.

[174] 4. Supporting 256QAM transmission method

[175] 4.1 Legacy MCS table

A base station can use a downlink control channel (eg, PDCCH / EPDCCH) to transmit a transport block size (TBS) for downlink data to a mobile station. At this time, the base station transmits the size information of the transport block, which is transmitted on the PDSCH, to the mobile station by combining the MCS index, which is the modulation and coding rate related information, with the resource allocation information.

For example, the MCS index (IMCS) field is composed of 5 bits, and radio resources can be allocated from 1 RB to 110 RB. Therefore, in case of non-MIMO in which MIMO is not applied, signaling for TBS (overlap size allowable) corresponding to 32 (state) xl lO (RB) is possible. However, three states (e.g., 29, 30, and 31) of MCS index fields transmitted in 5 bits are used to indicate a change in the modulation scheme upon retransmission. Therefore, in practice, only signaling for the TBS corresponding to 29x110 is possible.

In the current LTE / LTE-A system, three types of modulation schemes for supporting downlink data transmission are Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (16QAM), and 64QAM. The MCS index indicates the modulation order and the TBS index, and the MSC index indicates the same TBS at the switching point at which the modulation scheme is changed even if the modulation scheme is different. This is for efficient operation in various channel environments. This is because the change of the amount of information that can be transmitted per unit time is not large compared with the change of SINR (Signal to Interference plus Noise Ratio) at the switching point where the modulation scheme changes. Therefore, even if the modulation scheme is changed at the switching point, the same TBS is indicated and the radio resources can be efficiently allocated.

In order to indicate the actual transport block size, the MCS field (eg, IMCS) transmitted through the downlink control channel is mapped to another variable (ie, ITBS) in order to indicate TBS. do. Table 6 shows a 5-bit sized legacy MCS table currently used in the LTE / LTE-A system, and shows modulation and TBS index (ITBS) tables according to the MCS index (IMCS).

[180] [Table 6]

MCS Index Modulation Order TBS Index

MCS Q _m ^ TBS

0 2 0

1 2 1

2 2 2

3 2 3

4 2 4

5 2 5

6 2 6

7 2 7

8 2 8 9 2 9

10 4 9

1 1 4 10

12 4 1 1

13 4 12

14 4 13

15 4 14

16 4 15

17 6 15

18 6 16

19 6 17

20 6 18

21 6 19

22 6 20

23 6 21

24 6 22

25 6 23

26 6 24

27 6 25

28 6 26

29 2

30 4 reserved

31 6

However, since the current LTE / LTE-A system employs QPSK, 16QAM, and 64QAM only as a modulation scheme, it is necessary to define a new transport block size for 256QAM and IMCS definition for a new modulation order 8 in order to support 256 QAM. Should be. It is also necessary to define a new MCS index signaling to support the 256 QAM modulation scheme.

[182] 4.2 New MCS table definition for 256QAM support

Hereinafter, methods of supporting 256 QAM by adjusting the relationship between IMCS and ITBS without changing the size of the 5-bit MCS index field will be described. If retransmission is required first, a reserved state is required to change the modulation scheme without changing the TBS. To this end, one IMCS state (e.g., IMCS = 28) other than 29, 30, 31 of the IMCS of Table 6 may be used for 256QAM. That is, the IMCSs 28, 29, 30 and 31 can respectively designate the modulation scheme 256QAM, QPSK _: 16QAM, 64QAM (or QPSK, 16QAM, 64QAM, 256QAM) for the retransmission TBS. This is a way to minimize implementation complexity by redefining IMCS in existing implementations.

Table 7 below shows an example of a newly defined MCS table to support 256QAM.

[186] [Table 7]

Table 7 shows an example of a method of supporting 256QAM by adjusting the relationship between IMCS and ITBS without increasing the size of the existing MCS index field to support 256QAM. As shown in Table 7, ITBS having sequential sizes is allocated to the two IMCSs in which the modulation scheme of Table 6 and the modulation scheme of the DMC 64QAM and the 256QAM are changed.

[188] 4.3 IMCS signaling method

Since the IMCS fields of Table 6 to Table 7 have a size of 5 bits, even if the DCI format supported by the existing LTE / LTE-A system is used, it does not affect the legacy terminal significantly. However, both terminals that do not support 256QAM and terminals that support 256QAM It is not efficient to use only the new Table 7 for the management station. Therefore, the base station can provide data services to all terminals by selectively using Tables 6 and 7. [

Therefore, IMCS fields and signaling methods for TBS for legacy terminals that do not support 256QAM and legacy terminals that support 256QAM need to be defined differently. In embodiments of the present invention, Table 6 is referred to as a first table or a legacy table, and one of all tables newly defined in the embodiments of the present invention, including Table 7, is referred to as a second table or a new table do. That is, the first table is configured to support a legacy modulation scheme (e.g., QPSK, 16QAM, 64QAM), and the second table is configured to support a legacy modulation scheme and 256QAM.

In FIG. 10, it is assumed that the UE and the eNB hold the first table and the second table, respectively. In this case, the first table is as shown in Table 6 and defines a MCS index for a legacy terminal. The second table is shown in Table 7, and is a table for defining an MCS index for a terminal supporting 256QAM. Of course, a table configured to support 256QAM described in the embodiments of the present invention other than Table 7 may be used as the second table.

Referring to FIG. 10, a terminal and a base station perform a terminal capability negotiation process for negotiating whether to support 256QAM after initial connection with a base station (S 1010). In step S1010, the UE and the BS confirm that they support 256QAM, and assume that various parameters and / or fields for supporting 256QAM are exchanged.

After that, if the base station needs to transmit downlink data composed of 256QAM, the base station first transmits a physical layer signal (eg, PDCCH) including a 256QAM indicator indicating the use of 256QAM or a table identifier indicating a second table (E.g., a signal and / or an EPDCCH signal) or an upper layer signal (e.g., a MAC signal or an RRC signal) to the terminal (S1020).

In step S1020, the UE receiving the 256QAM indicator or the second table identifier indicating the use of 256QAM can recognize that downlink data transmitted from the base station is modulated to 256QAM. Therefore, the terminal can use the second table.

After that, the base station transmits a PDCCH signal and / or an EPDCCH signal including the IMCS to the UE. At this time, since the terminal already prepares the second table for 256QAM, the TBS according to the IMCS received from the second table can be derived (S1030).

The base station modulates and transmits downlink data (for example, a DL-SCH signal) according to the modulation order and the TBS informed to the UE through the IMCS. In step S1040, the MS receives and demodulates downlink data based on the IMCS received in step S1030.

In step S1030, the methods described in the section 4.1 or 4.2 can be applied to the method of signaling the IMCS. For example, according to the method described in Section 4.1 and Section 4.2, the existing legacy MCS table (ie, total 1 table) and the MCS / TBS index table (ie, the second table) to support 256QAM have a size of 5 bits . Therefore, The signaling of the PDCCH signal / EPDCCH signal including the IMCS can be performed in the same manner as the LTE / LTE-A system.

In step S1040, the base station modulates the eight bit streams into one modulation symbol using the 256QAM modulation scheme, maps the modulated modulation symbols to 256QAM constellation points, and transmits the modulation symbols to the terminal. The UE can decode the downlink modulation symbols according to the received IMCS.

In another embodiment, the base station may indirectly inform the terminal whether to use the 256QAM modulation scheme. For example, if a new transmission mode is defined for 256QAM, the UE can recognize that the 256QAM modulation scheme is used by notifying the UE of the new transmission mode through RRC signaling without explicit signaling as in step S1020 . In this case, step S1020 may not be performed.

[202] 5. Constellation Mapping Method

In FIG. 10, in order to perform step S 1040, OFDM signals or OFDM symbols transmitted through a PDSCH are mapped on a constellation and transmitted. That is, it is necessary to newly define how the OFDM signals transmitted in the 256QAM scheme are mapped on the constellation. In the following, design methods for constellation to support 256QAM will be described in detail.

The constellation for 256QAM defined in the embodiments of the present invention is defined as a method for expanding the constellation mapping method for 64QAM, thereby reducing the complexity of the constellation design. At this time, the QAM modulation scheme increases the transmission efficiency by mapping a plurality of bit streams to one modulation symbol. 64QAM maps 6 bits to one of 64 constellations, and 256QAM is transmitted by mapping 8 bits to 256 constellation points. [205] 5.164QAM constellation point design

Table 8 below shows constellation points of 64QAM. In the embodiments of the present invention, complex (a, b) represents a complex number a + j * b (a and b are integers), and sqrt (a) represents a symbol V. According to Table 8, the bit sequence [bO M b2 b3 b4 b5] = [0 1 1 0 1] consisting of 6 bits is complex (+ 7.0 / sqrt (42.0), -3.0 / sqrt Is mapped to the constellation point corresponding to " 0 "

+ 3.0 / sqrt (42.0), //! <B0bl b2 b3 b4 b5 = 000000 complex (+ 3.0 / sqrt (42.0) b3b4 b5 = 000001 complex (+ 1.0 / sqrt (42.0), + 3.0 / sqrt (42.0)), //! <b0bl b2b3 b4 b5 = 000010 complex (42.0), + 1.0 / sqrt (42.0), //! <B0blb2 b3 b4 b5 = 000011 complex (+ 3.0 / sqrt (42.0), + 5.0 / sqrt b0 blb2 b3 b4 b5 = 000101 complex (+0.0 / sqrt (42.0), +7.0 / sqrt (42.0) 5.0 / sqrt (42.0), // KbObl b2b3 b4 b5 = 000110 complex (+ l, 0 / sqrt (42.0), +7.0 / sqrt (42.0)), //! <B0bl b2 b3 b4 b5 = 000111 complex + 5.0 / sqrt (42.0), + 3.0 / sqrt (42.0)), //! <B0blb2b3b4b5 = 001000 complex (+5.0 sqrt = 0.0100 sqrt (42.0), + 3.0 sqrt (42.0), //! <B0blb2b3 b4 b5 = 001010 complex (+7.0 / sqrt (42.0), + 1.0 / sqrt / KbObl b2b3 b4 b5 = 001011 complex (+0.5 / sqrt (42.0), + 5.0 / sqrt (42.0)), //! <B0 bl b2 b3 b4 b5 = 001100 complex (+ 5.0 / sqrt / sqrt (42.0)), // KbObl b2 b 3 b4 b5 = 001101 complex (+7.0 / sqrt (42.0), + 5.0 / sqrt (42.0)), // KbObl b2 b _. 3b4 b5 = 001110 complex (+7.0 / sqrt (42.0), +7.0 / sqrt (42.0)), // KbObl b2b3 b4 b5 = 001111 complex (+ 3.0 / sqrt // o <bO bl b2 b3 b4 b5 = 010000 complex (+ 3.0 / sqrt (42.0), -1.0 / sqrt (42.0)), //! <bO bl bl b3 b4 b5 = 010001 complex sqrt (42.0), -3.0 / sqrt (42.0)), // KbObl b2b3 b4 b5 = 010010 complex (+1.0 / sqrt complex (+ 3.0 / sqrt (42.0), -5.0 / sqrt (42.0)), // bObl b2b3 b4 b5 = = 010100 complex (+ 3.0 / sqrt (42.0), -7.0 / sqrt <b0blb2b3b4b5 = = 010110 complex (+ 1.0 / sqrt (42.0), -5.0 / sqrt (42.0)), //! <b0blb2b3b4b5 = )), // KbObl b2 b3 b4 b5 = = 010111

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he he he he he he he he he he he

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o

If II II II II II 1) II II 1! ! 1 II! II 11 ff x>

r _\

Xi

i Xi

Ξ Ξ Ξ X) Ξ Ξ Ξ Ξ Ξ Ξ Ξ Ξ o o o o o o o

Xi

V V. V V V V V V V V V V V V V V V V V V V V V V

0 ¹¹⁰⁰¹ =

0 ^{0 ΐ 0 I t} - la

Example ^q o ^q ooo ^{i I} =

(5.0.0 / sqrt (42.0), -5.0 / sqrt (42.0)), //! <b0 bl b2 b3 b4 b5 = 111100

(7.0.0 / sqrt (42.0), -5.0 / sqrt (42.0)), //! <b0 bl2 b3 b4 b5 = 111101 complex b1 b3 b4 b5 = 111110 complex (-7.0 / sqrt (42.0), -7.0 / sqrt (42.0)), //! <b0 bl b2 b3 b4 b5 = 111111

[208] 5.2256QAM constellation point design

The bit mapping method for 256QAM constellation points can be designed using 64QAM bit mapping method. Since the 256QAM modulation scheme transmits two more bits to one modulation symbol than 64QAM, the constellation of 256QAM can be designed as shown in FIG. 11 or 12 according to a combination of two bits. 11 or 12 is a diagram illustrating an example of a constellation designing method for supporting a 256QAM modulation scheme.

[210] Also, Π is a simplified representation of constellation, and four quadrants are divided into 00, 10, 11, and 01, respectively. At this time, the constellation corresponding to 64QAM is arranged in the third quadrant represented by 11, and two bits [bO M] are added to design an 8-bit constellation. Then, we can design the constellation of the third quadrant by adding [1 0], [0 1], and [0] to [bObl] through X axis symmetry, Y axis symmetry, and symmetry of origin. Table 9 below shows one of the 256QAM constellation points to which the design method described in FIG. 11 is applied.

(13.0 / sqrt (170.0), + 13.0 / sqrt (170.0)), //! <B0bl b2 b3 b4 b5 b6 b7 = 00000000 complex (+13.0 / sqrt 15.0 / sqrt (170.0)), // KbObl b2 b3 b4 b5 b6 b7 = 00000001 complex (+15.0 / sqrt (70.0), +13.0 / sqrt (170.0)), //! <B0blb2 b3 b4 b5 b6 b7 = (13.0 / sqrt (170.0), +11.0 / sqrt (170.0)), // KbObl b2 b3b4b5 b6 b7 = 00000011 complex (+15.0 / sqrt (15.0 / sqrt (170.0), + 9.0 / sqrt (170.0)), // KbObl b2 b3 b4 b5 b6 b7 = 00000101 complex ) +11.0 / sqrt (170.0)), // KbObl b2 b3 b4 b5 b6 b7 = 00000110 complex (+15.0 / sqrt (170.0) (11.0 / sqrt (170.0), + 13.0 / sqrt (170.0)), // KbObl b2 b3 b4 b5 b6 b7 = 00001000 complex (+11.0 / sqrt // KbObl b2 b3 b4 b5 b6 b7 = 00001001

_/ O 03S90SSZAV _// un _o sH _O SM _ld

_{_{_{O / i AV 0SS90 S s /}}} : / n 0 2Ml> d / -3 0 s

O _/ SAV 0SS90SI _/ : _{/ 0} 2Ml> d _/ -3 ₀ sH

_{_{_{/ OAV 0SS90SSZ /: dsss2M l>}}} .. / / i) o6 (0) Q () 0L I (0 O Z v9sx b s- - '''('

(170.0), -15.0 / sqrt (I70.0)), II <b0bl b2b3 b4 b5 b6 b7 = 1 I10101 1 complex; -5.0 / sqrt (170.0), -11.0 / sqrt ), II, <b0 bl b2 b3 b4 b5 b6 b7 = 1 101 100 complex -5.0 / sqrt (170.0), -9.0 / sqrt (170.0)), II <b0bl b2 b3 b4 b5 b6 b7 = -7.0 / sqrt (170.0), -11.0 / sqrt (170.0)), in <b0bl b2 b3 b4 b5 b6 b7 = ), II <b0bl b2 b3 b4 b5 b6 b7 = 1 1 101 101 complex (-3.0 / sqrt (170.0), -3.0 / sqrt (170.0)), II <b0bl b2b3 b4 b5 b6 b7 = 100.0 complex (-3.0 / sqrt (170.0), -1.0 / sqrt (170.0)), II <b0bl b2 b3 b4 b5 b6 b7 = 1 1 10001 complex (-1.0 / sqrt ), II <b0bl b2b3 b4 b5 b6 b7 = 1 1 10010 compJex (-1.0 / sqrt (170.0), -1.0 / sqrt (170.0)), II <b0bl b2 b3 b4 b5 b6 b7 = complex (-3.0 / sqrt (170.0), -5.0 / sqrt (170.0)), II <b0 bl b2 b3 b4 b5 b6 b7 = I [ 170.0)), II < b0bl b2 b3 b4 b5 b6 b7 = 1 1 1 10101 complex (-1.0 / sqrt 0.0.0), -5.0 / sqrt (170.0)), II < b0bl b2 b3 b4 b5 b6 b7 = 1 1 101 10 complex (-1.0 / sqrt (170.0), -7.0 / sqrt <b0bl b2b3 b4 b5 b6 b7 = 1 101 101 complex (-5.0 / sqrt (170.0), -3.0 / sqrt (170.0)), II, <b0bl bl b3 b4 b5 b6 b7 = (170.0), -3.0 / sqrt (170.0), -1.0 / sqrt (170.0)), II <b0 bl b2 b3 b4 b5 b6 b7 = ), in <b0bl b2 b3 b4 b5 b6 b7 = 1 111010 complex (-7.0 / sqrt (170.0), -1.0 / sqrt (170.0)), //! <b0bl b2b3b4b5 b6 b7 = 1 1 1 1011 complex (-5.0 / sqrt (170.0), -5.0 / sqrt (170.0)), //! <b0bl b2b3 b4 b5 b6 b7 = 1 1 1 11 1100 complex (-5.0 / sqrt (170.0), -7.0 / sqrt (170.0)), //! <b0bl b2b3b4b5 b6 b7 = 1 1 1 1 1 101 complex (-7.0 / sqrt (170.0), -5.0 / sqrt (170.0)), //! <b0bl b2 b3 b4 b5 b6 b7 = 1] 1 1 1 1 10 complex (-7.0 / sqrt (170.0), -7.0 / sqrt (170.0)), //! <b0bl b2b3 b4 b5 b6 b7 = 1 1 1 1 1 1 1 1

FIG. 12 is a simplified representation of constellation diagrams, in which four quadrants are divided into 00, 10, 11, and 01, respectively. At this time, the constellation corresponding to 64QAM is arranged in the first quadrant represented by 00, and then the 256QAM constellation diagram of 8 bits length can be designed by adding two bits [bO bl]. Then, the constellation diagram of the first quadrant can be designed by adding [01], [10], and [1 1] to [bO bl] through X-axis symmetry, Y-axis symmetry and origin symmetry, respectively. Table 10 below shows one of the 256QAM constellation points to which the design method described in FIG. 12 is applied.

(170.0), + 11.0 / sqrt (170.0)), I IK b0 bl b2 b3 b4 b5 b6 b7 = 00000000 complex (+ 1.0 / sqrt (170.0) (9.0.0) / sqrt (170.0)), //! <B0 bl b2 b3 b4 b5 b6 b7 = 00000001 complex (+9.0 / sqrt b5 b6 b7 = 00000010 complex (+0.9 / sqrt (170.0), +9.0 / sqrt (170.0)), //! <b0 bl b2 b3 b4 b5 b6 b7 = 0000001 1

_/ O0 _S S _Z A _V 0SS9 _/ : §2μ1 £ 3 _{0Ϊ <Ϊ0 /} . / n _{) i ((} _{X / (} n ₍₎ O _Z J ₎ O _ill + du _i oo _b sx9 _J bs _{i '}

cr

_/ OAV 0SS90SSZ _//: sT0 _i s2Ml _/ - _i s ..

O _/ SZAV ₀ S _S90 S _// n ₀ 2M _/ -3 ₀ s

I 0 I

ΐ ^ΐ

I ^I 0

_/ O0SSZAV 0SS9 _/: §2¾12 _/ -3 _{0 <<0}

I ^0: ^{ΐ ΐ ΐ} ^I0 = (170.0), -15.0 / sqrt (170.0)), II <b0bl b2 b3 b4 b5 b6 b7 = 1 1 100101 complex (-7.0 / sqrt (170.0), -13.0 / sqrt , II <b0bl b2 b3 b4 b5 b6 b7 = 11 1001 10 complex (-7.0 / sqrt (170.0), -15.0 / sqrt (170.0)), II <b0bl b2 b3 b4 b5 b6 b7 = 1 1 1001 1 1 complex -3.0 / sqrt (170.0), -11.0 / sqrt (170.0)), II <b0bl b2 b3b4b5 b6 b7 = 1 101000 complex (-3.0 / sqrt (170.0), -9.0 / sqrt b3 b4 b5 b6 b7 = 1 1 101010 complex (-1.0 / sqrt (170.0), -11.0 / sqrt (170.0)), II <b0blb2 b3 b4 b5 b6 b7 = B3 b4 b5 b6 b7 = 1 1 10101 1 complex (-3.0 / sqrt (170.0), -13.0 / sqrt (170.0)), II <bObl b2 b3 b4 b5 b6 b7 = 1 101 101 100 complex (-1.0 / sqrt (170.0), -15.0 / sqrt (170.0)), in <b0bl b2 b3 b4 b5 b6 b7 = -13.0 / sqrt (170.0)), in <bObl b2b3 b4 b5 b6 b7 = 1 101 101 complex (-1.0 / sqrt (170.0), -15.0 / sqrt (170.0)), //! <bObl b2 b3 b4 b5 b6 b7 = 1 101 101 complex (-5.0 / sqrt (170.0), -5.0 / sqrt (170.0)), II <bO bl b2 b3 b4 b5 b6 hi = (0.04) / sqrt (170.0), -7.0 / sqrt (170.0)), II < bObl b2 b3 Mb5 b6 b7 = <bObl b2 b3 b4b5 b6 b7 = 1 1 10010 complex (-7.0 / sqrt (170.0), -7.0 / sqrt (170.0)), II <bObl b2 b3 b4 b5 b6 b7 = / sqrt (170.0), -1.0 / sqrt (170.0)), II < b0 bl b2 b3 b4 b5 b6 b7 = <b0 bl b2 b3 b4 b5 b6 b7 = 1 1 10101 complex (-7.0 / sqrt (170.0), -3.0 / sqrt (170.0)), II <b0 bl b2 b3 b4 b5 b6 b7 = -7.0 / sqrt (170.0), -1.0 / sqrt (170.0)), II <b0 bl b2 b3 b4 b5 b6 b7 = 1 1 101 101 complex (-3.0 / sqrt (170.0), -5.0 / sqrt B2 b3 b4 b5 b6 b7 = 1 1 1000 complex (-3.0 / sqrt (170.0), -7.0 / sqrt (170.0)), II <bObl b2 b3 b4 b5 b6 b7 = 1 1 1001 complex (-1.0 / sqrt (170.0), -5.0 / sqrt (170.0)), II <bObl b2 b3 b4 b5 b 6 b7 = 1 1 1 1 1010 complex (-1.0 / sqrt (170.0), -7.0 / sqrt (170.0)), //! <b0 bl b2 b3 b4 b5 b6 b7 = 1 1 101 101 complex (-3.0 / sqrt (170.0), -3.0 / sqrt (170.0)), //! <b0 bl b2 b3 b4 b5 b6 b7 = 1 1 1 1 1 100 complex (-3.0 / sqrt (170.0), -1.0 / sqrt (170.0)), //! <b0bl b2 b3 b4 b5 b6 b7 = 1 1 1 1 1 101 complex (-1.0 / sqrt (170.0), -3.0 / sqrt (170.0)), //! <b0bl b2 b3Mb5 b6 b7 = 1 1 1 1 1 1 10 10 complex (-1.0 / sqrt (170.0), -1.0 / sqrt (170.0)), //! <bO bl b2 b3 b4 b5 b6 b7 = 1 1 1 1 1 1 1 1

FIG. 13 is a diagram illustrating another method for designing constellation points for supporting a 256 QAM modulation scheme.

In FIG. 13, one of the smallest rectangles indicates a constellation point of the 256QAM modulation scheme. In Fig. 13, the X axis means the real axis and the y axis means the imaginary axis. In addition, the constellation points are arranged at intervals of 1, 3, 5, 7, 9, 11, 13, An 8-bit bit stream is modulated and coded at each constellation point and converted into one OFDM symbol / signal and then mapped. In this case, in FIG. 13, two bits for distinguishing each quadrant constitute a most significant bit (MSB), and four blocks in each quadrant are also composed of two next bits. In addition, each of the four blocks is again composed of four small blocks, which are also divided into two bits. And finally, the smallest blocks are separated into two bits, respectively, and the constellation points are indicated. Therefore, in the method of analyzing FIG. 13, two bits sequentially branching from two bits that divide four quadrants are divided, and the last eight bits divide one constellation point.

For example, referring to FIG. 13, first, the quadrant consists of two most significant bits [b0 bl]. At this time, the constellation points corresponding to 64QAM are arranged based on the above-described methods. In Fig. 13, constellation points of [b0 blb2 b3 b4 b5 b6 b7] = [0 0 1 1 0 0 1 1] are mapped to complex (+15 / sqrt (170), +15 / sqrt . The constellation point of [b0 bl b2 b3 b4 b5 b6 b7] = [1 0 0 1 0 0 0 1] is mapped to complex (-3 / sqrt (170), + 15 / sqrt do. In this way, all the constellation points shown in FIG. 13 can be distinguished.

The constellation mapping configuration method of FIG. 14 is the same as the method described in FIG. However, the values of the constellation points are different from those of FIG.

Referring to FIG. 14, first, the quadrant consists of [b0 bl] having two MSBs (Most Significant Bits). At this time, each quadrant has a constellation corresponding to 64QAM Points are arranged based on the methods described above. 14, the constellation point of [b0 bl b2 b3 b4 b5 b6 b7] = [0 0 1 1 0 0 1 1] is mapped to complex (+ 9 / sqrt (170), + 9 / sqrt . The constellation points of [bO bl b2 b3 b4 b5 b6 b7] = [1 0 0 1 0 0 0 1] are mapped to complex (-3 / sqrt (170), + 9 / sqrt do. In this way, the constellation points shown in Fig. 14 can be distinguished.

The constellation points shown in FIG. 14 can also be expressed as shown in the following Table 11. That is, in the 256QAM modulation system, 8 bits b (i), b (i + 1), b (i + 2), b (i + 3), b (i + i + 6) and b (i + 7) can be mapped as complex modulation symbols ^j Q ⁾ / where I denotes the real axis value and Q denotes the imaginary axis value.

[222J [Table 1 1]

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/ I ΟΐΟ / ΟΖΗΜΑ1:><Ι 0) S90 / SI0Z OAV 15 15 15 I -15 I 1011 1 1 1 1 I -15 | 15 | 1 11 1 1 11 1 I -15 I -15

[223] 5. Implementation Device

The apparatus described in FIG. 15 is a means by which the methods described in FIGS. 1 to 14 can be implemented.

A UE (User Equipment) may operate as a transmitter in an uplink and as a receiver in a downlink. Also, the eNB (eNB) can operate as a receiver in an uplink and operate as a transmitter in a downlink.

That is, the terminal and the base station include Tx modules 1540 and 1550 and Rx modules 1550 and 1570, respectively, to control transmission and reception of information, data and / or messages. And antennas 1500 and 1510 for transmitting and receiving information, data, and / or messages.

The terminal and the base station respectively include processors 1520 and 1530 for performing the embodiments of the present invention and memories 1580 and 1590 for temporarily or continuously storing the processing of the processor Respectively.

Embodiments of the present invention can be performed using the components and functions of the terminal and base station apparatuses described above. For example, the processor of the base station may perform the above-

In combination with the methods described in Section 4, MCS / TBS index tables for supporting 256QAM can be maintained and managed, and IMCS can be signaled to support 256QAM. Also, the processor of the base station and / or the terminal may map the OFDM symbol modulated by the 256QAM modulation scheme to the constellation mapping method described in FIGS. 11 to 14 and Tables 9 to 11, and transmit the same. For detailed methods, please refer to the explanation in Sections 1 to 4. The transmit and receive modes included in the UE and the BS include a L modulating and demodulating function for data transmission, a fast packet channel coding function, an Orthogonal Frequency Division Multiple Access (OFDMA) packet scheduling, a time division duplex TDD (Time Division Duplex) packet scheduling and / or channel multiplexing function. In addition, the terminal and base stations of Fig. I ⁵ may further include a low power RF (Radio Frequency) / IF ( Intermediate Frequency) mode.

In the present invention, a personal digital assistant (PDA), a cellular phone, a personal communication service (PCS) phone, a GSM (Global System for Mobile) phone, a WCDMA (Wideband CDMA) A hand-held PC, a notebook PC, a smart phone, or a multi-mode-multi-band (MM-MB) have.

Here, the smart phone is a terminal that has advantages of a mobile communication terminal and a personal portable terminal, and includes a terminal that integrates data communication functions such as calendar management, fax transmission / reception, and Internet access, which are functions of a portable terminal, It can mean. In addition, the multimode multiband terminal can operate both in a portable Internet system and other mobile communication systems (for example, Code Division Multiple Access (CDMA) 2000 system, WCDMA (Wideband CDMA) system, etc.) .

Embodiments of the present invention may be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs) Digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of firmware or software implementation, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure, or a function for performing the functions or operations described above. For example, the software code may be stored in the memory units 1580, 1590 and driven by the processors 1520, 1530. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various means already known.

The present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention. In addition, claims that do not have an explicit citation in the claims may be combined to form an embodiment or be included in a new claim by amendment after the filing.

[Industrial applicability]

Embodiments of the present invention can be applied to various wireless access systems. Examples of various wireless access systems include 3GPP (3rd Generation Partnership Project), 3GPP2, and / or IEEE 802.XX (Institute of Electrical and Electronic Engineers 802) systems. The embodiments of the present invention can be applied not only to the various wireless access systems described above, but also to all technical fields applying the various wireless access systems.

Claims

【Scope of Claim】

【Claim 1】

In a method for a transmitter to transmit a modulation symbol using the 256QAM (Quadrature Amplitude Modulation) modulation method in a wireless access system,

Modulating eight bit strings into one modulation symbol using the 256QAM modulation method;

mapping the modulation symbol to one of 256QAM constellation points; And transmitting the mapped modulation symbol,

The 256QAM constellation points are configured as shown in the following figure,

[floor plan]

， Modulation symbol transmission method.

【Claim 2】

According to clause 1 _: The 256QAM constellation points are,

A modulation symbol transmission method in which 64 64QAM constellation points are arranged in the first quadrant of the figure, and the 64QAM constellation points are configured by imaginary axis symmetry, real axis symmetry, and origin symmetry.

【Claim 3】

According to clause 2,

The transmitting end simultaneously manages a first table for supporting the legacy modulation method and a second table for supporting the 256QAM modulation method.

【Claim 4】

In paragraph 13,

The transmitting end transmitting a higher layer signal including an indicator indicating whether the 256QAM modulation method is supported; and

A modulation symbol transmission method further comprising selecting an MCS index indicating the 256QAM modulation method from the second table and transmitting it to a receiving end.

【Claim 5】

According to clause 4,

The MCS index is a modulation symbol transmission method displayed in 5 bit size.

【Claim 6】

According to clause 2,

A modulation symbol transmission method wherein the transmitting end is a base station and the receiving end is a terminal.

【Claim 7】 In a wireless access system, the transmitter transmits a modulation symbol using the 256QAM (Quadrature Amplitude Modulation) modulation method,

transmitter;

Including a processor to support the 256QAM modulation method,

The processor:

Eight bit strings are modulated into one modulation symbol using the 256QAM modulation method;

map the modulation symbol to one of the 256QAM constellation points;

Configured to transmit the mapped modulation symbol using the transmitter, wherein the 256QAM constellation points are configured as shown in the following figure,

[floor plan]

Transmitting stage. In paragraph 17,

The 256QAM constellation points are,

64QAM constellation points are placed in the first quadrant,

A transmitter configured by imaginary axis symmetry, real axis symmetry, and origin symmetry where the 64QAM constellation points are symmetrical.

【Claim 9】

In clause 8,

The transmitting terminal simultaneously manages a first table for supporting the legacy modulation method and a second table for supporting the 256QAM modulation method.

【Claim 10】

According to clause 9,

The transmitter controls the transmitter to transmit a higher layer signal including an indicator indicating whether the 256QAM modulation method is supported;

A transmitting end selects an MCS index indicating the 256QAM modulation method from the second table and transmits it to the receiving end.

【Claim 11】

According to clause 10,

The MCS index is expressed in 5-bit size at the transmitting end.

[Claim 12]

According to clause 8,

The transmitting end is a base station and the receiving end is a terminal.